Conventionally, devices, which perform drive control of an independent winding multi-phase motor (for example, a six-line three-phase motor) capable of controlling current of an armature winding of each phase provided in a motor stator independently from each other, have been known. When such a motor is used, it is possible to solve a lack in voltage without using a booster circuit and to acquire higher output of the motor. In addition, it is possible to increase capacity and to increase a maximum rotational velocity.
A technique has been proposed in which a pseudo-square wave current, obtained by superimposing a harmonic component on a winding of each phase, is caused to flow in an independent winding multi-phase motor as described above so as to enable drive of a motor to continue even when a current or a voltage is abnormal in a winding of any phase (PTL1).